1. Field of the Invention
The present invention relates generally to a zipper pull tab connected to a slider and specifically to a separable zipper pull tab having two separate portions secured together such that the two portions separate when sufficient force is exerted on the pull tab thereby protecting the zipper and simplifying subsequent repair.
2. Description of the Related Art
A zipper pull tab assembly traditionally includes a slider that slides along the zipper halves, called stringers, to engage and disengage interlocking links. The slider is manipulated by a pull-tab structure. Zipper pull tabs are used on a wide variety of products, including clothing and storage units such as luggage. As luggage is handled by its owner and manipulated by various handling systems, as at airports, one or more pull tabs on the luggage may become caught in a conveyor, hooked or entangled with other luggage or simply caught by some other mechanism.
Unless the force of these possible entanglements is controlled, a pull tab, the slider to which it is attached and part of the zipper itself could be ripped off the luggage.
Frequently, either or both the slider and pull tab were made from a pot metal that is not bondible but which fractures and breaks when bent. Consequently, making the slider with lugs that enclose a pull tab to allow the pull tab to pivot, or having the pull tab itself formed with a lug that encloses part of the slider can break if undue force is applied to the slider/pull tab assembly, usually to the pull tab itself.
Much difficulty has been experienced in the zipper industry with zipper systems due to the weakness of the link between the zipper pull tab and the slider or slide fastener. The link has a tendency to break under normal or excessive force placed on the system. Accordingly, when a zipper pull tab, having a normal separate link fastener, is subjected to unusual stress or force, often the pin element of the lock or fastener links are damaged. Such damage is costly to repair or replace an element of the system.
Several typical zipper pull designs are disclosed in Aoki et al., U.S. Pat. No. 4,920,615 ("Aoki"); Marinsky et al., U.S. Pat. No. 2,270,068 ("Marinsky"); and Minami, U.S. Pat. No. 4,949,434 ("Minami").
Aoki discloses a slide fastener slider having a supporting body and a pull tab support, such that the pull tab can be attached quickly and yet be removable. The pull tab support is shaped so as to define a gap for loosely receiving an annular portion of the pull tab and has an inner surface engaging structure. The pull tab has a substantially U-shaped resilient member having at the opposite ends fitting joints for fitting engagement with the engaging means, to thus close the gap. While Aoki discloses a zipper pull in which a resilient member can be removably attached to a support body, it does not address or solve the problem of how to prevent damage to the zipper pull if excessive forces pull or yank on the pull tab itself. Therefore, if the pull tab is yanked off the slide, costly replacement or repair must be undertaken.
Marinsky discloses a lock slider for a zipper where the slider may be maintained against movement longitudinally along the zipper under normal tensions which tend to separate the links 15 hold on stringers 14. This reference discloses a positive engagement provided by the zippers between the slider and the links of the fastener that does not yield to abnormal stresses placed upon the fastener stringers. With unusual transverse stress, the fasteners can separate, and the pin 17 will break, the baring apertures 19, 19a can break or the entire slider could disengage from links 15, 15a.
Minami discloses a slide fastener slider which has a "c" pull tab which is thinned across a portion of the tab making that area easily bendable when subjected to severe pressure or force and hence preventing injury the user's body when the user accidentally strikes the pull tab. The concept is illustrated in FIG. 2 of the reference. Minami's zipper pull still does not adequately address the problems associated with the entire pull tab being broken from the slider or the slider itself being broken away from the zipper links.
Accordingly, in the conventional zipper pull design, when the zipper pull is forced from the slider, the zipper or slider or perhaps both must be removed and replaced or repaired, which is costlier than simply replacing the zipper pull tab.